Справочник Пользователя для Samsung 3.5" hard disk drives

DISK DRIVE OPERATION 
 

SpinPoint V40 Product Manual

 

32

 
The read/write channel functions include a time base generator, AGC circuitry, asymmetry correction 
circuitry (ASC), analog anti-aliasing low-pass filter, analog to digital converter (ADC), digital FIR filter, 
timing recovery circuits, Viterbi detector, sync mark detection, 32/34 rate block code ENDEC, serializer and 
de-serializer, and write pre-compensation circuits.  Servo functions include servo data detection and PES 
demodulation.  Additionally the 88C5200 contains specialized circuitry to perform various parametric 
measurements on the processed read signal.  This allows for implementation of self-tuning and optimization 
capability in every drive built using the 88C5200. 
 
A 9-bit NRZ interface is provided to support high speed data transfers to and from the controller.  
Programming of the 88C5200 is performed through a serial interface.  The serial interface is also used to read 
various channel parameters that are computed on the fly. 
 

 
The time base generator provides the write frequency and serves as a reference clock to the  
synchronizer during non-read mode. 
 

 
The AGC accepts a differential signal from the pre-amp, and provide a constant output  
amplitude to the analog filter.  It’s capable of accepting signal ranges from 40 mV to 400 mVppd. 
 

 
The ASC circuit is designed to correct for amplitude asymmetry introduced by MR heads.  The  
compensation range of this circuit is +/-45%.  This circuit allows optimal bias current to be used  
independent of the asymmetry effect. 
 

 
The 7

th

 order equal-ripple analog filter provide filtering of the analog signal from AGC before it’s  

being converted to digital signal with the ADC.  It’s main function is to avoid aliasing for the 
 ADC circuit. 
 

 
The output of the analog filter is quantified using a 6 bit FLASH ADC.  The digitized data is then 
 equalized by the FIR to the NPV target response for Viterbi detection.  The FIR filter consists of 7 
independent programmable taps.